Debate has been going on for quite some time now as to what are the most appropriate targets for systolic blood pressure to reduce cardiovascular events among people with increased cardiovascular risk. To try and resolve the issue, the SPRINT (1) investigators randomly assigned 9361 subjects with increased cardiovascular risk scores and a systolic blood pressure of 130 mm Hg or higher, to a systolic blood-pressure target of less than 120 mm Hg (“intensive treatment”) or a target of <140 mm Hg (“standard treatment”). Patients with diabetes were not included in the study. The primary composite endpoint was the occurrence of myocardial infarction or other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes. At 1 year follow up, the mean systolic blood pressure was 121.4 mm Hg in patients receiving the “intensive-treatment” and 136.2 mm Hg in the “standard-treatment” group. As the former group showed a significantly lower rate of the primary composite outcome compared with “standard treatment” patients, the study was stopped earlier than planned, at a median follow-up of 3.26 years (hazard ratio with “intensive treatment”, 0.75; 95% confidence interval [CI], 0.64 to 0.89; P<0.001). All-cause mortality was also significantly lower in the “intensive-treatment” group (hazard ratio, 0.73; 95% CI, 0.60 to 0.90; P=0.003). This group however also showed higher rates of adverse events i.e. hypotension, syncope, electrolyte abnormalities, and acute kidney injury or failure, but not of injurious falls, than the “standard-treatment” group. The SPRINT investigators have thus concluded that “among patients at high risk for cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg, resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause, although significantly higher rates of some adverse events were observed in the intensive-treatment group”. (SPRINT was funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01206062.) – These important results are likely to have an impact on medical practice worldwide.
- The SPRINT Research Group. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. N Engl J Med 2015. DOI: 10.1056/NEJMoa1511939
Health professionals involved in the management of patients with hypertension knew from observational studies that there is a progressive increase in cardiovascular disease risk with blood pressure above 115/75mmHg.1 However, there was limited data from randomized controlled trials suggesting beneficial effects with lowering blood pressure below 140/90mmHg.
The recent publication of the Systolic Blood Pressure Intervention Trial (SPRINT),2 has provided the much awaited evidence needed to revise blood pressure (BP) lowering targets to help improve cardiovascular outcomes.
The SPRINT researchers randomly assigned 9361 individuals with a systolic blood pressure ≥130mmHg and increased cardiovascular risk to ‘intensive treatment’ (i.e. target BP <120mmHg) or ‘standard treatment’ (i.e. target BP <140mmHg). The researchers excluded individuals with resistant hypertension, diabetes mellitus and previous strokes. The mean BP at baseline was almost identical in the two treatment groups at 140/78mmHg. At 1 year of follow up the mean BP was 121.4/68.7 mmHg in the ‘intensive treatment’ group and 136.2/76.3 mmHg in the ‘standard treatment’ group. The study was stopped early after a median follow-up of 3.26 years as individuals in the ‘intensive-treatment’ group had a 25% lower relative risk of major cardiovascular events (95% confidence intervals: 11 to 36; P<0.001), as compared with those assigned to the standard- treatment group. Furthermore, individuals in the ‘intensive-treatment’ group had a 27% lower relative risk of all cause mortality (95% confidence intervals: 10 to 40; P=0.003). As may be expected with intensive BP lowering, individuals in the ‘intensive treatment’ group had higher rates of adverse events, including hypotension, syncope, electrolytes disturbances, and acute kidney injury.
The SPRINT trial will change practice and the task now is for hypertension societies to revise their guidelines to reflect these findings and a more challenging task is for healthcare professionals to improve hypertension control and reduce cardiovascular risk disease in patients with high blood pressure.References
- Lewington S, Clarke R, Qizilbash N, Peto R, Collins R. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet 2002;360:1903-1913.
- Sprint Research Group. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. N Engl J Med 2015;373:2103-2116.